This project started as a personal itch. Mouse software kept telling me one number, but moving the cursor by hand across a ruler often told a different story entirely. Manufacturer utilities round figures, apply their own scaling, and rarely explain how they arrived at the number shown on screen — so I built something that skips the guesswork and measures directly, using nothing but a ruler and a browser tab.
How the Measurement Actually Works
The idea behind it is simple. You move your mouse a known physical distance — five inches, ten centimeters, whatever you happen to have a ruler for — and the browser measures how many pixels the cursor actually traveled across the screen. Divide one by the other and you get a direct reading of what your sensor is actually producing, rather than a number pulled from a settings panel that may or may not match what the hardware is doing underneath. No downloads, no drivers, no account required. Just a measurement you can trust, taken in under thirty seconds.
Why a Tool Like This Needed to Exist
Anyone who has tried to match a sensitivity setting between two different mice, or compare their own setup to a professional player’s, runs into the same problem eventually: the number printed on the box or shown in the manufacturer’s software isn’t always the number the sensor is actually producing. Firmware updates, driver conflicts, and even the specific USB port you’re plugged into can all introduce small discrepancies. For casual use, that gap rarely matters. For competitive gaming, design work, or anyone trying to reproduce an exact feel across different hardware, it matters quite a bit.
That’s really the whole motivation here: closing that gap with a direct physical measurement instead of trusting a label. It’s a small, almost mundane problem, but it was one nobody seemed to be solving in a straightforward way — most resources either repeated the manufacturer’s numbers uncritically or buried the explanation in jargon that made the actual mechanics harder to understand, not easier.
A Small Testing Suite, Not Just One Tool
Since the first version went live, the project has grown to include a handful of related testers: click speed, polling rate, input jitter, reaction time, and a few calculators for translating sensitivity between games and devices. None of this was planned from the start — it grew naturally, because once you start measuring one part of a mouse setup, the rest of the questions tend to follow. If you’ve ever wondered whether your polling rate is actually doing what the packaging claims, or whether your click speed holds up under sustained testing, the same philosophy applies: measure it directly rather than take someone else’s word for it.
Being Honest About Accuracy
No browser-based measurement tool is going to be laboratory-grade precise, and I’d rather say that plainly than oversell it. Browser timing, display refresh rates, and the physical consistency of your own hand movement all introduce some variance between individual tests. Running a measurement three or four times and averaging the results gives a far more reliable picture than trusting any single pass, and that’s the approach I’d recommend to anyone using these tools seriously.
The goal was never to replace a professional testing lab. It was to give anyone with a mouse and a ruler a way to get meaningfully closer to the truth than a settings panel alone can offer, and to explain the reasoning clearly enough that you understand what the number actually means once you have it.
Who This Is Actually For
Competitive players trying to pin down an exact eDPI before a tournament, designers who spend all day doing precision work and want consistent cursor behavior, and people who are simply curious whether their new mouse is doing what the box claims — all of that falls within scope here. You don’t need any technical background to use any of the tools; the explanations are written the way I’d want something explained to me, without unnecessary jargon or inflated claims about precision the tools don’t actually have.
What’s Changed, and What Hasn’t
The underlying measurement logic keeps getting refined as I learn more about how different browsers and operating systems handle raw input — Windows, macOS, and various browser engines all have their own quirks, and accounting for them properly takes ongoing attention rather than a one-time build. What hasn’t changed is the basic premise: everything here stays free, nothing requires an account, and new tools only get added when they solve a real version of the same underlying problem rather than just padding out a menu.
If something looks off, if a number doesn’t match what you’re seeing on your own setup, or if there’s a feature or a game you think deserves its own calculator, the Contact page reaches me directly. I read everything that comes through it.
— John Paul